Quantitative analysis of histological preparations of the rectal mucosa were carried out in 52 patients with gastrointestinal symptoms. Follow-up investigation demonstrated no signs of chronic inflammatory bowel disease. The variables recorded in the histological preparations in the 52 patients were the diameter (minor axis) of 10 consecutive, transversally cut glands, the space of lamina propria between glands, the number of glands per high-power field, and the number of nuclei in 10 consecutive areas of lamina propria (between glands). The histological state of the rectal mucosa in individual patients was quantitatively defined as the score resulting from the sum of the values in each of the above-mentioned variables. Similarly to the rectal mucosa from asymptomatic patients, the rectal mucosa from the 52 symptomatic patients had scores of 21 or less. These composite data form the basis for a comparative quantitative study of the rectal mucosa from patients with various chronic inflammatory conditions of the rectum.